client server socket structured message c#

Question

Helllo guys, I'm creating client-server game using sockets. I'm trying to use structured messages, then serialize and deserialize them, there is 3 strings in my structure. My code serializes first string, but mess up two following ones. I been told that my structure might have enough space space only for one string.

My message structure:

public struct Message_PDU
{
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10101)]
    public string commandID;
    public string playerIndex;
    public string score;
}; 

Serialize method

     private byte[] Serialize(Object myObject)
    {
        int size = Marshal.SizeOf(myObject);
        IntPtr ip = Marshal.AllocHGlobal(size); //allocate unmanaged memory equivelent to the size of the object
        Marshal.StructureToPtr(myObject, ip, false); //marshal the object into the allocated memory
        byte[] byteArray = new byte[size];
        Marshal.Copy(ip, byteArray, 0, size); //place the contents of memory into a byte[]
        Marshal.FreeHGlobal(ip); //free unmanaged memory
        return byteArray;
    }

Sending message code:

            String szdata1 = "--";
            String szdata2 = AlliasText.Text;
            String szdata3 = "1";



            Message_PDU myPDU = new Message_PDU();
            myPDU.commandID = szdata1;
            myPDU.playerIndex = szdata2;
            myPDU.score = szdata3;
            byte[] byData = Serialize(myPDU); //convert structure into a byte[]
            m_ClientSocket.Send(byData, SocketFlags.None);

I tried to increase SizeConst, but it didn't work. Debugging shows that only first string gets serialized. Thank you

Answer 1

thank for trying to help. My course leader helped me to sort it out. Basically, I marshalized only first string instead of each one of them, because I thought that I am marshalizing whole structure.

Message structure should look like this:

public struct Message_PDU
{
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 101)]
public string commandID;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 101)]
public string playerIndex;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 101)]
public string score;
}; 

Also, SizeConst is just charachters length sent in the message, and it's important to make as short as possible. Thank you again, I hope it helps someone in the future.